Depends what features/protection you are looking for and your budget. The Strikeback alarm starts at around £600. The Clifford 330x1 is a reasonable base at around £299 fitted and can be upgraded with additional sensors like glass break detection, dual proximity sensors and tilt sensors etc but there’s no rear PIR sensor which you may want for a motorhome. The Autowatch 695RLC costs a little more at around £400 fitted but includes features more suited to a motorhome, it also has the option of a wireless rear PIR sensor.